High Nonlinearity and High Voltage Gradient ZnO Varistor Ceramics Tailored by Combining Ga2O3, Al2O3, and Y2O3 Dopants

作者：Zhao, Hongfeng; Hu, Jun; Chen, Shuiming; Xie, Qingyun; He, Jinliang^*

来源：Journal of the American Ceramic Society, 2016, 99(3): 769-772.

DOI：10.1111/jace.14110

• GRAIN

This paper deals with the electrical characteristics of rare-earth-doped ZnO varistor ceramics. Multiple donor dopants (Al3+, Ga3+, and Y3+) were employed to improve the comprehensive performance of ZnO varistor ceramics. The leakage current of rare-earth-doped ZnO varistor ceramics decreased noticeably with Ga2O3 dopants. The Ga3+ dopant occupies the defect sites of grain boundaries and increases the barrier potential of ZnO varistor ceramics, so the leakage current is effectively inhibited. Y2O3 is primarily located around the grains, which restrains ZnO grain growth, increasing the voltage gradient. The Al3+ goes into the lattices of ZnO grains, decreasing the grain resistance; thus, the residual voltage ratio can be controlled at low levels under a high impulse current. With the combined incorporation of Al3+, Ga3+, and Y-3, excellent electrical properties of ZnO varistor ceramics can be acquired with a nonlinearity coefficient of 87, voltage gradient of 517 V/mm, leakage current of 0.96 A/cm(2), and residual voltage ratio of 1.60. These rare multiple donor dopants can aid in engineering high-quality ZnO varistors.

• 出版日期2016-3
• 单位清华大学